After many years of effort in solving the molecular structure of crotoxin complex crystal, we have concluded that the crystal has variable motifs which make it impractical for structural determination by classical electron crystallographic procedures. In order to obtain independent confirmation that the unit cell motifs vary across the crystals, we have initiated an effort to study this specimen in an atomic force microscope. This technology is well advanced in the laboratory of Professor A. Engel. We hope to evaluate if this approach will provide a useful indication of the suitability of thin protein crystals for electron crystallographic analysis.